This invention is directed to hydraulic raising and lowering mechanisms for dump body or dump bed trucks, and the like, and is particularly directed to providing improvements in the structural arrangement of the lifting members of such a lifting mechanism, or raising and lowering mechanism, which is manifestly different from similar mechanisms heretofore known in the prior art, by mounting the extensible lift cylinder or lift cylinders on the pivoted lifting stabilizer arm which raises the dump frame so that the lift cylinder travels up and down in an arcuate path with the lifting stabilizer arm, whereby a minimum of travel distance of the extensible cylinder which is also connected to the dump frame is obtained, thus providing faster unloading of the truck dump body.